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Carry flag manipulation instructions – NEC PD750008 User Manual

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CHAPTER 11 INSTRUCTION SET

SKE XA,@HL

Function: Skip if A = (HL) and X = (HL+1)

Skips the immediately following instruction if the contents of the A register match the data at the data memory

location addressed by the HL register pair, and the contents of the X register match the data at the next address

in data memory.

However, if the contents of the L register are odd- numbered, an address with the lowest-order bit ignored

is specified.

SKE A,reg

Function: Skip if A = reg

Skips the immediately following instruction if the contents of the A register match the contents of register

reg (X, A, H, L, D, E, B, C).

SKE XA,rp’

Function: Skip if XA = rp’

Skips the immediately following instruction if the contents of the XA register pair match the contents of

register pair rp’ (XA, HL, DE, BC, XA’, HL’, DE’, BC’).

11.4.8 Carry Flag Manipulation Instructions

SET1 CY

Function: CY <– 1

Sets the carry flag.

CLR1 CY

Function: CY <– 0

Clears the carry flag.

SKT CY

Function: Skip if CY = 1

Skips the immediately following instruction if the carry flag is set to 1.

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